The Centers for Disease Control and Prevention (CDC) released results from the 2011 Youth Risk Behavior Surveillance Survey (YRBSS/YRBS). This survey is used to track youth–risk behavior trends throughout the nation, every other year in odd years, ever since 1991. Overall, most unhealthy, high-risk behaviors have been trending downward since 1991, but some risk behaviors increased slightly in 2011. Access the full CDC report for details, and note that summaries are contained at the beginning of the report, while data tables are located near the end.

Less than half (47.4 percent) of students have ever had sexual intercourse, which means 52.6 percent have never had sex.

Only one-third (33.7 percent) are currently sexually active (sexual intercourse during the 3 months before the survey).

One in seven high school teens (or 15.3 percent) had sexual intercourse with four or more people during their life. About one-quarter (24.1 percent ) of all 12th graders have had sex with four or more people.

Nearly one in every 10 high school students (9.4 percent) experienced dating violence.

About one in seven females in 12th grade (14.5 percent) have been forced to have sexual intercourse during their life.

Of the 35 states participating in the survey, Delaware was the state with the highest number of high school teens who ever had sex (59 percent), while Hawaii had the highest number of teens who have never had sex (63 percent).

Marijuana Use:

Close to a quarter of all high school students (23.1 percent) "currently use" marijuana (past 30 days before survey), which represents the highest rate since 2001 (23.9 percent).

Two in every five students have "ever used" or tried marijuana (39.9 percent).

Suicide:

28.5 percent—Felt sad or hopeless (up from a slight drop in 2009 at 26.1 percent)

15.8 percent—Seriously considered attempting suicide (up from 2009 at 13.8 percent; however, the trend has steadily declined from a high of 29 percent in 1991).

7.8 percent—Attempted suicide one or more times (up slightly from the 2007-2009 rate of 6.9 percent and 6.3 percent, respectively).